Oh, gosh. I never meant to imply that I thought GM should put a monster size 6.0L V8 into the SRX.

I just meant that a vehicle that already does rather well with just a 3.6L V6, would do equally well with an appropriately sized hybrid system.

IMHO, basing a hybrid off of a whopping 6.0L V8, isn't exactly meeting my definition of environmentally friendly.

 

Driving a car with an internal combustion engine isn't environmentally friendly.

I agree that most owners of Escalades have no reason to have such a large vehicle. But the only sensible way to stop the excess environmental destruction is to boost the price of the thing that causes the damage: gasoline. In the meantime, a hybrid Escalade reduces the damage done.

 

While I agree in principal with this statement I disagree with the assertion.

It's not gasoline that causes the damage it's the emissions from vehicle. If you can design a vehicle that runs on gas, but greatly reduces emmissions then you can have a tremendous impact on the environment.

That is exactly why I am a proponent of Hybrid technology in all vehicles (big, small, slow or fast). The Lexus Hybrid models are great examples of vehicles that don't necessarily give you maximum mpg, but they do GREATLY reduce the emissions from the vehicle, which has a huge impact on the environment.

 

What is there that is specific to hybrid technology that causes a great reduction in emissions other than the reduced fuel consumption? Let's keep this on a per gallon of fuel consumed basis. Doesn't a gallon of gas burned in a hybrid produce pretty much the same amount of CO2 as gas burned in a comparable non-hybrid? What about the hydrocarbons, CO, and NOx? I would think they would be the same, but I do not know for sure.

 

I follow that thought. Thing is, if you already have a 6.0L system developed and you want to launch a Cadillac application, you put it in the vehicle that CAN accept a 6.0L, if it makes sense to go to market with that product. Vehicles based on other engine designs / displacements have to wait until the development resourses are available to engineer new applications.

The whole point of it, though, is that it spends a lot of time operating as a 3.0L 4-cylinder. The Active Fuel Management (AFM) system shuts off 4 cylinders when they are not needed. The trick is to size the engine such that the available reserve torque in 4-cylinder mode is sufficient to move the vehicle appropriately. If it were a 5.0L V8, it might not spend as much time operating as a 2.5L 4-cyl. At 3.0L the engine is strong enough to manage on 4 cylinders for a greater portion of its normal operating range. Using the same rationale, the 303 hp 5.3L AFM V8 powered Chevrolet Impala SS gets better highway fuel economy (28 mpg) than the 233 hp 3.9L AFM V6 Impala LTZ (27 mpg). The SS spends more time running on a 2.65L 4-cylinder than the LTZ spends running on a 2.0L 3-cylinder.

Peace,

Martin

 

This is a bad assumption.

The amount of emmissions that your car puts out is not just related to the consumption of fuel. How cleanly and effeciently the combustion process is has a big effect on the emmission levels. Alot of what comes out of your tailpipe is becaue the fuel did not completely burn during the combustion process. This is why there are a few SULEV NON-hybrid vehicles. The engines have been designed to reduce emmissions by burning off more of the fuel during combustion.

This is also why newer vehicles in general are producing less emmission compared to 10 years ago. Today's Camry puts out less emmissions than 10 years ago and MPG is roughly the same.

http://auto.howstuffworks.com/catalytic-converter1.htm

The main emissions of a car engine are:

• Nitrogen gas (N2) - Air is 78-percent nitrogen gas, and most of this passes right through the car engine.<
• Carbon dioxide (CO2) - This is one product of combustion. The carbon in the fuel bonds with the oxygen in the air.<
• Water vapor (H2O) - This is another product of combustion. The hydrogen in the fuel bonds with the oxygen in the air.<

These emissions are mostly benign (although carbon dioxide emissions are believed to contribute to global warming). But because the combustion process is never perfect, some smaller amounts of more harmful emissions are also produced in car engines:

• Carbon monoxide (CO) - a poisonous gas that is colorless and odorless<
• Hydrocarbons or volatile organic compounds (VOCs) - produced mostly from unburned fuel that evaporates Sunlight breaks these down to form oxidants, which react with oxides of nitrogen to cause ground level ozone (O3), a major component of smog.<
• Nitrogen oxides (NO and NO2, together called NOx) - contributes to smog and acid rain, and also causes irritation to human mucus membranes"

Here is another good link
http://science.howstuffworks.com/question407.htm

 

I think I was misunderstood. Let me rephrase my question.


How will the emissions of a 2007 Camry (non-hybrid) burning one gallon of gasoline compare to the emissions of a 2007 Camry Hybrid burning one gallon of gasoline? I was just asking what is was that was specific to hybrids that reduced emissions. Is there a difference?


Thanks.

 

I read an excellent explanation, but can't remember where. If I figure it out I'll post the link. In the meanwhile I'll answer as best as I can remember. This is very simplified, and probably has a lot of holes in it. Hopefully, I'll find the article

Most engines run on what is called an Otto cycle in which the all four cycles are the same length. When operating at low power the input is restricted, not operating at peak efficiency and some of the combustion products are not fully burned. The Toyota Camry hybrid uses a Miller-Atkinson cycle engine. An Atkinson cycle engine is an engine in which the four cycles have two different compression ratios. It's a lot more efficient than an Otto cycle engine, but doesn't have the same torque. This doesn't make it well suited for a regular car, but with the aid of electric motors it's ideal for hybrids.

The Miller-Atkinson engine achieves the goal of uneven compression ratio by allowing the input valves to stay open at the beginning of the compression cycle to expel some air and gas during low power operation, to be used later. Being able to vary how long the valves stay open allows an ideal air-fuel mixture each cycle to be fully combusted, thereby giving lower emissions.

I'm sorry. I'm sure someone is going to read this and laugh, but that's the best I can do from memory. I think I originally found it through Wikipedia, but couldn't find it just now.

 

In addition to the above explanation, the HV battery in the hybrid can be used to heat up the catalytic converter much quicker than in a conventional vehicle. Catalytic converters work better when they are warm. The sooner it gets to temp the less pollution you emit in that time frame.

 

i'd never heard that the propulsion battery in any hybrids is used to preheat or accelerate the heating of the catalytic converter. really?! nice idea, one way or the other.